Couldn't create follow request

[tabeckers]

During checkup with @DonZandbergen

[tabeckers]

Seems to only happen to user DonZandbergen as requester (id = 34c62918-d5ce-45aa-b9c7-41d44c896cc9)

[tabeckers]

This happens when the profile is set to private and the user follow mode is set to decline_all. Because our backend currently isn't a no-op backend, an invalid follow request will return an error.

What happens is the following:

• No follow request exists in the database.

• User A follows user B.

• The frontend thinks the follow request statis is pending.

• Declined follow request exists in the database.

• Refresh the page or go to another followable location in the app.

• User A tries to follow user B

• Backend tries to create a new entry but one already exists, so we get a duplicate key exception.

The conclusion is that this issue lies with our backend. The current error 500 response is caught by our application and no more crashes occur. This was due to the lack of an error handler in rxjava's subscribe() method. An error handler that does nothing has been added, this is fine for now.